In recent years, opportunities of treating images as digital data have rapidly increased along with enhancement of computing power, and progress in networking technology. Image information obtained by a digital camera or image information which has been digitized from photographic film or prints using a scanner can be readily edited, or supplemented with text or illustrations on a computer. Examples of hard copy material used to prepare a hard copy based on such digitized image information include a sublimation type thermal print, melt type thermal print, ink-jet print, electrostatic transfer type print, thermoautochrome print and silver halide color photographic material. Of these, silver halide photographic material (hereinafter, also referred to as photographic material) has greatly superior characteristics such as high sensitivity, superior tone, superior image lasting quality and lower cost, compared to other print material and therefore, is broadly employed for preparation of high quality hard copy prints.
Digitized image information can be readily edited on a computer, leading to increased opportunities of manipulating images comprised of a mixture of images based on captured data of people, landscapes, still-life (hereinafter, also denoted as scenic images) and characters (specifically, thin small black text). Accordingly, natural reproduction of scenic images and character reproduction without blurring are simultaneously required in image output based on digital data.
Recently, various digital exposure devices to conduct exposure based on digitalized image information, have become commercially available. Further, a number of new digital image exposure devices have been developed along with the progress in exposure light sources and control devices. Of these digital image exposure devices, devices employing a light source exhibiting a sharp light source wavelength distribution, such as laser or LED are becoming the main trend. Although the spread of various digital image exposure devices has launched a variety of imaging devices on the market, the kind of lasers and LED installed therein has not been uniform, and exposure devices are usually different in exposure wavelength. Further, in many cases, there are differences in various terms such as overlap ratio of exposure beams, exposure time interval between adjacent pixels, and exposure time and intensity per pixel, even when employing the same exposure light source. Therefore, when employing different exposure devices, quality of the reproduced prints fluctuates, resulting specifically in color bleeding at the edges of text characters, and improvement of quality in such fluctuation has been sought.
Further, according to the kinds of digital exposure devices, since it is difficult to stably control the amount of light at the low end of the exposure scale, in some cases, print density in highlighted areas fluctuates even when using the same digital data, and it is also desired to minimize these fluctuations. These problems may be minimized by optimization of photographic material with respect to each exposure device or each exposure condition, however, the variety of exposure devices on the market is large, and continues to increase. Therefore, the standardization of photographic material is not a realistic approach. Under these circumstance, desired is a silver halide photographic material which can provide an excellent print exhibiting sharp character edges with less bleeding, and superiority in color reproduction, employing any exposure device and under any printing condition, and a method for forming an image using the same.
Recently, on the other hand, mini-lab shops, so called “One Hour Photo”, featuring a short time processing (being within 45–60 min.), are becoming common. For this reason, use of color paper having a high silver chloride content and exhibiting superior photographic processing characteristics has become widespread. Color paper having such high silver chloride content tends not to exhibit high sensitivity under above digital exposure, compared to usual analog exposure, and further, exhibits problems in gradation, fogging, storage stability before exposure, and pressure resistance to scratching, as an example. Thus, various improving technologies have been disclosed (please refer, for example, to Patent Documents 1–3), however, sufficient effects are not obtained in actual practice. Specifically, problems are in sensitivity, gradation (by extension, color reproduction), and storage stability, and thus, early solutions are desired.
An object of the present invention is to provide a silver halide photographic material and a method for forming an image using the same, whereby a color print is obtained by exposure and photographic processing based on digital information, and particularly to provide a silver halide photographic material having high sensitivity, excellent gradation, storage stability and pressure resistance while exhibiting superiority in reproduction of text and colors, and a method for forming an image using the same.
Patent Document 1: Unexamined Japanese patent Application Publication (hereinafter, referred to as JP-A) 2002-182326
Patent Document 2: JP-A 2002-162707
Patent Document 3: JP-A 2001-188311